In the Pathway a + B  C

Multiple Choice

In the pathway A + B  C + D, enzyme X facilitates the reaction.If compound D is further metabolized through a series of steps to form compound Z, and compound Z inhibits enzyme X, one could conclude that

A) enzyme X is subject to feedback stimulation.
B) compound D is an allosteric activator of the first reaction.
C) compound Z is a competitive inhibitor of the first reaction.
D) enzyme X is subject to feedback inhibition.
E) compound D is a coenzyme in the first reaction.